246 Mr. T. V. Wollaston on tJie Coleopterous Fauna 



llieir complete divergence from the poUtus of more northern 

 latitudes ; so that it Avould consequently appear that the true 

 melanoccjylialus^ although cited by myself for the Madeiran, 

 Canarian, and Cape -Verde groups, has not yet been oliserved 

 in any of them, the examples from the first and second 

 archipelagos being referable to the jwh'fus of Kiister, whilst 

 those from the third contain two additional forms, of which 

 (although recently enunciated by Dr. Sharj)) it may perhaps 

 be useful here to give the characters afresh. The species 

 alluded to are as follows : — 



PMJhydrus Wollastoni. 



P. subovalis, parum convexns, iiitidus, niger (aut fusco-niger) sed iu 

 limbo gradatim dilutior, ubiquc crobrc ct subtilitcr puiictatus 

 (punctis in clytris vix remotioribiis) ; capito niaciilis duabns 

 parvis latcralibus ante oeulos, autennis (clava excopta), palpis 

 tarsisqiic picoo-testaceis ; pcdibus piceis ; coleoptcris scriebus 

 tribus irregularibus punctoruni inajoium utrinquc longitudinaliter 

 notatis. 



Long. Corp. lin. circa 2\. 



PMUn/dnif! mclnnoecpJwlus, Woll. [uec Oliv.], Col. Hcsp. 44 (18G7). 

 'Wolhixtoni, Sharp, Aim. Nat. Hist. ser. 4. vol. v. p. 16 (1809). 



Hah'dat ins. S. Antonio, S. Yicentc, S. lago, ct Brava, a Dom. J. 

 Gray et meipso captus. 



Ohs. Species P. politumf'K.n^i. (in ins. CanariensibusMadercnsibusque, 

 necnon in Hispania regionibiisque contiguis lectum) prima facie 

 simulaus, sod corporc minore, snbbreviore, vix minus nitido ct 

 vix minus convcxo, intcrdum in elytris subdistinctius pimctulato, 

 prothorace subbrcviore, palpis tarsisque gracilioribus, necnon 

 unguiculis (in ntroque sexn vix diversis) minoribns denticuloquc 

 minore subtus armatis dignoscitur. 



This is apparently the common PliUhydrus of the Cape- 

 Verde archipelago ; and we may expect that it will be found 

 to be universal wherever there arc streams and pools of suffi- 

 cient importance not to be totally obliterated during the drier 

 seasons. Having neglected, however, Avhen compiling my 

 ' Coleoptera PIes])cridum,' to examine it with any great amount 

 of care, I fell into the error of regarding it as a rather small 

 state of the species which is so general throughout the Ma- 

 deiran and Canarian groups ; and since that species was iden- 

 tified by Aube, many years ago, with the European melano- 

 cephalus, I have invariably cited it as such, and consequently 

 looked upon this representative from the Cape Verdcs as a 

 mere depauperated phasis of the same. Yet the recent labours 

 of Dr. Sharp have shown, as above mentioned, not only that 

 I was mistaken in accepting too readily the determination of 

 Aub(5 as regards the Madeiran and Canarian PhilhyclruSj but 



